0000.993 (0) Creation of backups of directories: beginning
0000.996 (0) Beginning creation of dump of plugins (split every: 400 Mb)
0001.240 (0) Remaining entities to add to zip file: 200 directories, 1347 files
. . .
0009.283 (0) Created plugins zip (0) - 11449.1 Kb in 8.3 s (1381.7 Kb/s)
0009.286 (0) Beginning creation of dump of themes (split every: 400 Mb)
0009.338 (0) Remaining entities to add to zip file: 54 directories, 442 files
. . .
0010.783 (0) Created themes zip (0) - 2768.2 Kb in 1.5 s (1851.5 Kb/s)
0010.786 (0) Beginning creation of dump of uploads (split every: 400 Mb)
0010.920 (0) Remaining entities to add to zip file: 16 directories, 1299 files
. . .
0046.134 (0) Created uploads zip (0) - 98433 Kb in 35.3 s (2785 Kb/s)
0046.136 (0) Looking for candidates to back up in: /home5/digitdt6/public_html/blog
0046.137 (0) finding files: .htaccess: adding to list
0046.138 (0) finding files: symbiostock_ipn: adding to list
0046.139 (0) finding files: symbiostock_keyword_info.xml: adding to list
0046.140 (0) finding files: wp-trackback.php: adding to list
0046.141 (0) finding files: wp-signup.php: adding to list
0046.142 (0) finding files: license.txt: adding to list
0046.143 (0) finding files: symbiostock_image_info.xml: adding to list
0046.144 (0) finding files: symbiocard.xml: adding to list
0046.144 (0) finding files: symbiostock_image_sitemap.xml: adding to list
0046.145 (0) finding files: wp-settings.php: adding to list
0046.146 (0) finding files: wp-config.php: adding to list
0046.147 (0) finding files: symbiostock_keyword_info.csv: adding to list
0046.148 (0) finding files: error_log: adding to list
0046.149 (0) finding files: wp-includes: adding to list
0046.150 (0) finding files: index.php: adding to list
0046.150 (0) finding files: wp-admin: adding to list
0046.152 (0) finding files: symbiostock_network: adding to list
0046.162 (0) finding files: symbiostock_image_info.csv: adding to list
0046.164 (0) finding files: wp-comments-post.php: adding to list
0046.164 (0) finding files: symbiocard.csv: adding to list
0046.165 (0) finding files: wp-content: skipping: this is the wp-content directory
0046.166 (0) finding files: wp-links-opml.php: adding to list
0046.167 (0) finding files: wp-config-sample.php: adding to list
0046.168 (0) finding files: images: adding to list
0046.169 (0) finding files: wp-load.php: adding to list
0046.170 (0) finding files: symbiostock_xml_cache: skipping: excluded by options
0046.171 (0) finding files: wp-activate.php: adding to list
0046.172 (0) finding files: symbiostock_network.csv: adding to list
0046.173 (0) finding files: symbiostock_image_sitemap_1.xml: adding to list
0046.174 (0) finding files: wp-login.php: adding to list
0046.175 (0) finding files: wp-blog-header.php: adding to list
0046.176 (0) finding files: wp-cron.php: adding to list
0046.177 (0) finding files: wp-mail.php: adding to list
0046.178 (0) finding files: readme.html: adding to list
0046.179 (0) finding files: plr_data_files: adding to list
0046.180 (0) finding files: symbiostock_rf: adding to list
0046.181 (0) finding files: xmlrpc.php: adding to list
0046.182 (0) Beginning creation of dump of wpcore (split every: 400 Mb)
0046.325 (0) Remaining entities to add to zip file: 102 directories, 1504 files
. . .
0197.373 (0) Zip size is at/near split limit (401 Mb / 400 Mb) - bumping index (from: 0)
0197.378 (0) Created wpcore zip (0) - 410589.6 Kb in 151.2 s (2715.6 Kb/s)
. . .
0347.279 (0) Zip size is at/near split limit (403.9 Mb / 400 Mb) - bumping index (from: 1)
0347.281 (0) Created wpcore zip (1) - 413553.2 Kb in 149.9 s (2758.8 Kb/s)
. . .
0492.685 (0) Zip size is at/near split limit (407 Mb / 400 Mb) - bumping index (from: 2)
0492.686 (0) Created wpcore zip (2) - 416804.7 Kb in 145.4 s (2866.5 Kb/s)
. . .
?Assessing process run time and adjusting?
0573.969 (0) The time we have been running (574) is approaching the resumption interval (600) - increasing resumption interval to 604
0573.971 (0) The scheduled resumption is within 45 seconds - will reschedule
0573.974 (0) Rescheduling resumption 1: moving to 649 seconds from now (1378270660)
0573.977 (0) To decrease the likelihood of overlaps, increasing resumption interval to: 604 + 45 = 649
0573.978 (0) A useful amount of data was added after this amount of zip processing: 20.5 s (normalised: 16.9 s, rate: 2627.5 Kb/s)
. . .

Shortly after this it looks as if they restarted the process and check to see what's already been created, at the end of this check is the following:

1225.168 (1) Beginning creation of dump of wpcore (split every: 400 Mb)
1225.169 (1) File exists (/home5/digitdt6/public_html/blog/wp-content/updraft/backup_2013-09-03-2037_digital_bristles_30be799c288a-wpcore4.zip.tmp), but was apparently not modified within the last 30 seconds, so we assume that any previous run has now terminated (time_mod=1378270053, time_now=1378270662, diff=609)
1225.286 (1) backup_2013-09-03-2037_digital_bristles_30be799c288a-wpcore.zip: Zip file already exists, with 1086 files
1225.431 (1) backup_2013-09-03-2037_digital_bristles_30be799c288a-wpcore2.zip: Zip file already exists, with 1134 files
1225.454 (1) backup_2013-09-03-2037_digital_bristles_30be799c288a-wpcore3.zip: Zip file already exists, with 1177 files
1225.467 (1) backup_2013-09-03-2037_digital_bristles_30be799c288a-wpcore4.zip.tmp: Zip file already exists, with 1215 files
. . .

Then they assess if they can batch larger chunks:

1259.311 (1) Performance is good - will increase the amount of data we attempt to batch (time=9.83086490631, normalised_time=7.05540316017, max_time=598, data points known=1, old_max_bytes=45353204, new_max_bytes=209715200)
1259.315 (1) Adding batch to zip file (UpdraftPlus_BinZip): over 200 Mb added on this batch (205.4 Mb, 1504 files batched, 28 (38) added so far); re-opening (prior size: 61097.9 Kb)
. . .
After a few of those, they decide that's big enough chunks
1329.461 (1) A useful amount of data was added after this amount of zip processing: 28 s (normalised: 27.4 s, rate: 7463.3 Kb/s)
1329.463 (1) Performance is good - but we will not increase the amount of data we batch, as we are already at the present limit (time=27.9838480949, normalised_time=27.4411270654, max_time=598, data points known=1, max_bytes=209715200)
...

1249.956 (1) Zip size is at/near split limit (416.1 Mb / 400 Mb) - bumping index (from: 3)
1249.958 (1) Created wpcore zip (3) - 426136.5 Kb in 24.8 s (17191.8 Kb/s)
. . .
1302.252 (1) Zip size is at/near split limit (396.6 Mb / 400 Mb) - bumping index (from: 4)
1302.254 (1) Created wpcore zip (4) - 406085.7 Kb in 52.3 s (7765.3 Kb/s)
. . .
1355.143 (1) Zip size is at/near split limit (385.7 Mb / 400 Mb) - bumping index (from: 5)
1355.145 (1) Created wpcore zip (5) - 394955 Kb in 52.9 s (7467.5 Kb/s)
. . .
1407.558 (1) Created wpcore zip (6) - 393899.8 Kb in 52.4 s (7515.4 Kb/s)
1407.562 (1) Adding batch to zip file (UpdraftPlus_BinZip): over 200 Mb added on this batch (205 Mb, 1504 files batched, 20 (157) added so far); re-opening (prior size: 0 Kb)
. . .
1459.131 (1) Zip size is at/near split limit (392.4 Mb / 400 Mb) - bumping index (from: 7)
1459.133 (1) Created wpcore zip (7) - 401801 Kb in 51.6 s (7790.8 Kb/s)
. . .
1500.043 (1) Zip size is at/near split limit (392.7 Mb / 400 Mb) - bumping index (from: 8)
1500.044 (1) Created wpcore zip (8) - 402161.6 Kb in 40.9 s (9830.4 Kb/s)
. . .
1540.727 (1) Zip size is at/near split limit (386 Mb / 400 Mb) - bumping index (from: 9)
1540.728 (1) Created wpcore zip (9) - 395215 Kb in 40.7 s (9714.6 Kb/s)
. . .
1581.656 (1) Created wpcore zip (10) - 357637.2 Kb in 40.9 s (8738.4 Kb/s)
1581.659 (1) Beginning backup of other directories found in the content directory (index: 0)
1581.660 (1) Looking for candidates to back up in: /home5/digitdt6/public_html/blog/wp-content
1581.661 (1) finding files: uploads: skipping: this is the uploads directory
1581.662 (1) finding files: symbiostock_file_download.php: adding to list
1581.663 (1) finding files: index.php: adding to list
1581.664 (1) finding files: themes: skipping: this is the themes directory
1581.665 (1) finding files: plugins: skipping: this is the plugins directory
1581.665 (1) finding files: plupload: adding to list
1581.666 (1) finding files: updraft: skipping: this is the updraft directory
1581.667 (1) finding files: upgrade: skipping: excluded by options
1581.703 (1) Remaining entities to add to zip file: 11 directories, 55 files
1581.775 (1) /home5/digitdt6/public_html/blog/wp-content/updraft/backup_2013-09-03-2037_digital_bristles_30be799c288a-others.zip.tmp: size is now: 0.20 Mb
1581.780 (1) Created others zip (0) - 162.5 Kb in 0.1 s (1457.1 Kb/s)
. . .
1581.786 (1) Saving backup status to database (elements: 20)
1581.788 (1) Resuming creation of database dump
1581.797 (1) Table wp_options: Total expected rows (approximate): 388
1581.857 (1) Table wp_options: Total rows added: 388 in 0.07 seconds
1581.859 (1) Table wp_options: finishing file (backup_2013-09-03-2037_digital_bristles_30be799c288a-db-table-wp_options.table.gz)
1581.872 (1) Table wp_users: Total expected rows (approximate): 4
1581.875 (1) Table wp_users: Total rows added: 4 in 0.01 seconds
1581.876 (1) Table wp_users: finishing file (backup_2013-09-03-2037_digital_bristles_30be799c288a-db-table-wp_users.table.gz)
1581.887 (1) Table wp_usermeta: Total expected rows (approximate): 83
1581.893 (1) Table wp_usermeta: Total rows added: 83 in 0.01 seconds
1581.894 (1) Table wp_usermeta: finishing file (backup_2013-09-03-2037_digital_bristles_30be799c288a-db-table-wp_usermeta.table.gz)
1581.904 (1) Table wp_commentmeta: Total expected rows (approximate): 0
1581.906 (1) Table wp_commentmeta: Total rows added: 0 in 0.01 seconds
1581.907 (1) Table wp_commentmeta: finishing file (backup_2013-09-03-2037_digital_bristles_30be799c288a-db-table-wp_commentmeta.table.gz)
1581.917 (1) Table wp_comments: Total expected rows (approximate): 13
1581.923 (1) Table wp_comments: Total rows added: 13 in 0.01 seconds
1581.925 (1) Table wp_comments: finishing file (backup_2013-09-03-2037_digital_bristles_30be799c288a-db-table-wp_comments.table.gz)
1581.937 (1) Table wp_links: Total expected rows (approximate): 4
1581.943 (1) Table wp_links: Total rows added: 4 in 0.02 seconds
1581.945 (1) Table wp_links: finishing file (backup_2013-09-03-2037_digital_bristles_30be799c288a-db-table-wp_links.table.gz)
1581.952 (1) Table wp_postmeta: Total expected rows (approximate): 31389
1583.382 (1) Table wp_postmeta: Total rows added: 31389 in 1.43 seconds
1583.384 (1) Table wp_postmeta: finishing file (backup_2013-09-03-2037_digital_bristles_30be799c288a-db-table-wp_postmeta.table.gz)
1583.393 (1) Table wp_posts: Total expected rows (approximate): 1758
1583.759 (1) Table wp_posts: Total rows added: 1758 in 0.37 seconds
1583.762 (1) Table wp_posts: finishing file (backup_2013-09-03-2037_digital_bristles_30be799c288a-db-table-wp_posts.table.gz)
1583.771 (1) Table wp_term_relationships: Total expected rows (approximate): 12229
1584.081 (1) Table wp_term_relationships: Total rows added: 12229 in 0.32 seconds
1584.083 (1) Table wp_term_relationships: finishing file (backup_2013-09-03-2037_digital_bristles_30be799c288a-db-table-wp_term_relationships.table.gz)
1584.093 (1) Table wp_term_taxonomy: Total expected rows (approximate): 1870
1584.177 (1) Table wp_term_taxonomy: Total rows added: 1870 in 0.09 seconds
1584.179 (1) Table wp_term_taxonomy: finishing file (backup_2013-09-03-2037_digital_bristles_30be799c288a-db-table-wp_term_taxonomy.table.gz)
1584.187 (1) Table wp_terms: Total expected rows (approximate): 1853
1584.267 (1) Table wp_terms: Total rows added: 1853 in 0.09 seconds
1584.269 (1) Table wp_terms: finishing file (backup_2013-09-03-2037_digital_bristles_30be799c288a-db-table-wp_terms.table.gz)
1584.280 (1) Table wp_ss_images: Total expected rows (approximate): 461
1584.315 (1) Table wp_ss_images: Total rows added: 461 in 0.04 seconds
1584.317 (1) Table wp_ss_images: finishing file (backup_2013-09-03-2037_digital_bristles_30be799c288a-db-table-wp_ss_images.table.gz)
1584.320 (1) backup_2013-09-03-2037_digital_bristles_30be799c288a-db-table-wp_options.table.gz: adding to final database dump
1584.357 (1) backup_2013-09-03-2037_digital_bristles_30be799c288a-db-table-wp_users.table.gz: adding to final database dump
1584.359 (1) backup_2013-09-03-2037_digital_bristles_30be799c288a-db-table-wp_usermeta.table.gz: adding to final database dump
1584.361 (1) backup_2013-09-03-2037_digital_bristles_30be799c288a-db-table-wp_commentmeta.table.gz: adding to final database dump
1584.362 (1) backup_2013-09-03-2037_digital_bristles_30be799c288a-db-table-wp_comments.table.gz: adding to final database dump
1584.364 (1) backup_2013-09-03-2037_digital_bristles_30be799c288a-db-table-wp_links.table.gz: adding to final database dump
1584.366 (1) backup_2013-09-03-2037_digital_bristles_30be799c288a-db-table-wp_postmeta.table.gz: adding to final database dump
1584.639 (1) backup_2013-09-03-2037_digital_bristles_30be799c288a-db-table-wp_posts.table.gz: adding to final database dump
1584.715 (1) backup_2013-09-03-2037_digital_bristles_30be799c288a-db-table-wp_term_relationships.table.gz: adding to final database dump
1584.790 (1) backup_2013-09-03-2037_digital_bristles_30be799c288a-db-table-wp_term_taxonomy.table.gz: adding to final database dump
1584.808 (1) backup_2013-09-03-2037_digital_bristles_30be799c288a-db-table-wp_terms.table.gz: adding to final database dump
1584.828 (1) backup_2013-09-03-2037_digital_bristles_30be799c288a-db-table-wp_ss_images.table.gz: adding to final database dump
1584.845 (1) backup_2013-09-03-2037_digital_bristles_30be799c288a-db.gz: finished writing out complete database file (576 Kb)
1584.848 (1) Total database tables backed up: 12
1584.850 (1) Saving backup history
1584.854 (1) backup_2013-09-03-2037_digital_bristles_30be799c288a-plugins.zip: plugins: This file has not yet been successfully uploaded: will queue
1584.855 (1) backup_2013-09-03-2037_digital_bristles_30be799c288a-themes.zip: themes: This file has not yet been successfully uploaded: will queue
1584.856 (1) backup_2013-09-03-2037_digital_bristles_30be799c288a-uploads.zip: uploads: This file has not yet been successfully uploaded: will queue
1584.858 (1) backup_2013-09-03-2037_digital_bristles_30be799c288a-wpcore.zip: wpcore: This file has not yet been successfully uploaded: will queue
1584.859 (1) backup_2013-09-03-2037_digital_bristles_30be799c288a-wpcore2.zip: wpcore: This file has not yet been successfully uploaded: will queue
1584.865 (1) backup_2013-09-03-2037_digital_bristles_30be799c288a-wpcore3.zip: wpcore: This file has not yet been successfully uploaded: will queue
1584.866 (1) backup_2013-09-03-2037_digital_bristles_30be799c288a-wpcore4.zip: wpcore: This file has not yet been successfully uploaded: will queue
1584.867 (1) backup_2013-09-03-2037_digital_bristles_30be799c288a-wpcore5.zip: wpcore: This file has not yet been successfully uploaded: will queue
1584.868 (1) backup_2013-09-03-2037_digital_bristles_30be799c288a-wpcore6.zip: wpcore: This file has not yet been successfully uploaded: will queue
1584.869 (1) backup_2013-09-03-2037_digital_bristles_30be799c288a-wpcore7.zip: wpcore: This file has not yet been successfully uploaded: will queue
1584.869 (1) backup_2013-09-03-2037_digital_bristles_30be799c288a-wpcore8.zip: wpcore: This file has not yet been successfully uploaded: will queue
1584.870 (1) backup_2013-09-03-2037_digital_bristles_30be799c288a-wpcore9.zip: wpcore: This file has not yet been successfully uploaded: will queue
1584.872 (1) backup_2013-09-03-2037_digital_bristles_30be799c288a-wpcore10.zip: wpcore: This file has not yet been successfully uploaded: will queue
1584.872 (1) backup_2013-09-03-2037_digital_bristles_30be799c288a-wpcore11.zip: wpcore: This file has not yet been successfully uploaded: will queue
1584.873 (1) backup_2013-09-03-2037_digital_bristles_30be799c288a-others.zip: others: This file has not yet been successfully uploaded: will queue
1584.875 (1) backup_2013-09-03-2037_digital_bristles_30be799c288a-db.gz: db: This file has not yet been successfully uploaded: will queue
1584.876 (1) Requesting upload of the files that have not yet been successfully uploaded (16)
. . .
Upload to dropbox in chunks then deleting the  local files. After a couple of files get uploaded without interruption, it gets to 27.6% of the uploads.zip and is interrupted and has to start the process over. Checks where it is and picks up with 
2009.653 (2) This is a resumption: 27787264 bytes had already been uploaded
2009.654 (2) Dropbox: Attempt to upload: backup_2013-09-03-2037_digital_bristles_30be799c288a-uploads.zip to: backup_2013-09-03-2037_digital_bristles_30be799c288a-uploads.zip
2010.995 (2) Dropbox chunked upload exception: Submitted input out of alignment: got [27787264] expected [28311552]
2010.996 (2) Dropbox alignment error: tried=27787264, wanted=28311552; will attempt recovery
2014.522 (2) Dropbox chunked upload: 28.6 % uploaded (RHOwvTQsbjMw9dfQKj4LMA, 28835840)

That finishes and then the next file gets 7.7% done and it looks as if it's interrupted again

This process repeats many times. Here are the upload time reports

1651.029 (1) Dropbox: File upload success (backup_2013-09-03-2037_digital_bristles_30be799c288a-plugins.zip): 11449 Kb in 65s (173 Kb/s)
1669.060 (1) Dropbox: File upload success (backup_2013-09-03-2037_digital_bristles_30be799c288a-themes.zip): 2768 Kb in 17s (155 Kb/s)
2428.075 (2) Dropbox: File upload success (backup_2013-09-03-2037_digital_bristles_30be799c288a-uploads.zip): 98433 Kb in 418s (235 Kb/s)
6155.016 (7) Dropbox: File upload success (backup_2013-09-03-2037_digital_bristles_30be799c288a-wpcore.zip): 410589 Kb in 48s (8450 Kb/s)
9546.307 (11) Dropbox: File upload success (backup_2013-09-03-2037_digital_bristles_30be799c288a-wpcore2.zip): 413553 Kb in 75s (5472 Kb/s)
12079.250 (14) Dropbox: File upload success (backup_2013-09-03-2037_digital_bristles_30be799c288a-wpcore3.zip): 416804 Kb in 535s (779 Kb/s)
15024.641 (19) Dropbox: File upload success (backup_2013-09-03-2037_digital_bristles_30be799c288a-wpcore4.zip): 426136 Kb in 24s (17635 Kb/s)
17956.368 (23) Dropbox: File upload success (backup_2013-09-03-2037_digital_bristles_30be799c288a-wpcore5.zip): 406085 Kb in 193s (2097 Kb/s)
20618.401 (27) Dropbox: File upload success (backup_2013-09-03-2037_digital_bristles_30be799c288a-wpcore6.zip): 394955 Kb in 93s (4233 Kb/s)
23200.722 (30) Dropbox: File upload success (backup_2013-09-03-2037_digital_bristles_30be799c288a-wpcore7.zip): 393899 Kb in 597s (659 Kb/s)
26702.518 (35) Dropbox: File upload success (backup_2013-09-03-2037_digital_bristles_30be799c288a-wpcore8.zip): 401801 Kb in 535s (750 Kb/s)
29924.021 (40) Dropbox: File upload success (backup_2013-09-03-2037_digital_bristles_30be799c288a-wpcore9.zip): 402161 Kb in 8s (49111 Kb/s)
32243.116 (43) Dropbox: File upload success (backup_2013-09-03-2037_digital_bristles_30be799c288a-wpcore10.zip): 395215 Kb in 227s (1738 Kb/s)
32415.123 (43) Dropbox: File upload success (backup_2013-09-03-2037_digital_bristles_30be799c288a-others.zip): 162 Kb in 2s (61 Kb/s)
32422.525 (43) Dropbox: File upload success (backup_2013-09-03-2037_digital_bristles_30be799c288a-db.gz): 582 Kb in 7s (81 Kb/s)
35341.485 (47) Dropbox: File upload success (backup_2013-09-03-2037_digital_bristles_30be799c288a-wpcore11.zip): 357637 Kb in 403s (886 Kb/s)